Cambrian explosion: “Tulip animal” had unique feeding system

Siphusauctum has a long stem, with a calyx – a bulbous cup-like structure – near the top that encloses an unusual filter feeding system and a gut. The animal is thought to have fed by filtering particles from water actively pumped into its calyx through small holes. The stem ends with a small disc which anchored the animal to the seafloor. Siphusauctum lived in large clusters, as indicated by slabs containing over 65 individual specimens.

“Most interesting is that this feeding system appears to be unique among animals. Recent advances have linked many bizarre Burgess Shale animals as primitive members of many animal groups that are found today, but Siphusauctum defies this trend. We do not know where it fits in relation to other organisms,” said lead author O’Brien.

Apparently, there are over 1100 specimens in this Burgess Shale (western Canada) find.